Combining two data sources into one or making a parent and child relation with two different sources

[edster (Edgar Lucero)]

Hello,

So just to set some context around this. We are trying to work around the limitation of returning only at most 10k results during a search and with filters due to having an immense amount of data and it also coming from multiple indices.

Could I join multiple indices with different fields into one? Sounds like a mess but I figured I'd ask if it's possible.

The second idea is instead of using the child/parent join with the documents if it could be used with two indices. Is this also feasible or is there some other solution.

[spinscale (Alexander Reelsen)]

Have you considered using search_after and just running several requests using Point in Time?

[edster (Edgar Lucero)]

So due to time constraints and current setup on our spring boot side we were siding with using the Reindex API in conjunction with the parent-child join, however, the parent child join is a bit confusing. As in using the join_field or is that a said an actual field.

This is from an example I saw in a different post:
if(ctx._source.parent_id != null){ctx._routing = ctx._source.parent_id; ctx._source.join_field= params.cjoin}else{ctx._source.join_field = params.parent_join}",
"params" : {
"cjoin" :{
"name": "child_message",
"parent": 1
},
"parent_join" : "parent_message"

}